Method of making tubes.



No. 835,420. PATENTED NOV. 6, 1906. N. HEID.

METHOD 0F MAKING TUBES.

APPLICATION FILED JAN. 6. 1906.

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NICOLAUS HEID, OF STOCER-AU, AUSTRIA-HUNGARY.

METHODl OF MAKING TUBES.

Specification of Letters Patent.

Patented Nov. 6, 1906.

Application filed January 6, 1906. Serial N o. 294.865.

To (all wiz/0m, it' 11i/Ly concern:

Be it known that I, NICOLAUs HEID, a subject of the Emperor of Germany,residing at Stockerau, in Lower` Austria-Hungary, have invented certainnew ments in method of Making Tubes, of which the following is aspecification.

In the known methods of making tubes from spirally-wound metallic stripsit is absolutely necessary to solder the-seams or overlap ing edges ofthe tubes in order to make t em erfectly tight and resisting to highinternal) pressure. This soldering was ordinarily effected in suchamanner that the tube was removed from the winding-mandril and wasimmersed in a bath of molten soldering metal or by using for theproduction of the tubes either ordinary metallic strips or metallicstrips coated with soldering metal, which strips are immersed in thesolderingbath during the winding operation, so that the winding and thesoldering operations take place simultaneously. However, neither of thetwo methods of soldering is capable of producing a perfect or uniformintimate soldering of the overlapping surfaces of the edges of thestrips or of the seams. In the case of the first-named method the liquidsoldering metal will not penetrate between the surfaces of the stripedges, because these surfaces are lying too tightly one upon the other,so that the soldering will take place only at the ends of the edgesurfaces and not on the whole surfaces. In the case of the secondmethod, no matter whether ordinary metallic strips or strips connectedwith soldering metal have been employed, the liquidv soldering metalwill be squeezed out from between the adjacent surfaces of the stripedges in conse uence of the high pressure employed during t e windingoperation, so that at the places of the seam there will remain too smalluantities of solder for producing a good reliable soldering connection.Besides the solder squeezed out from between the strip edges is liableto solder the tube to the mandril,so that it will be impossible ordifficult to remove the tube from the mandril.

Finally, the heat which is required for the soldering operation has-aprejudicial effect on the windlng apparatus.

and useful Improve- The accompanying drawing shows by way of example atube made according to this method in side elevation and partly insection.

The im roved process is essentially carried out as follows: The metallicstrip a, coated with an easily-fusible metal -either entirely or only onits edges in the breadth corresponding to the overlap ing surfaces-forinstance, a cold-rolled steelpstripcoated with tin, zinc, or lead-iswound up spirally into a tube while it is in a cold condition-that is tosay, when the soldering metal is solidifiedwhereupon the tube removedfrom the mandril is immersed in a bath of molten soldering metal-such,as for instance, tin, zinc,lead,or alloys of these metals. Inconsequence of this immersion the tube becomes heated, and the edges bb', which form the connectingsurfaces of the spiral strip and may,ifnecessary, be provided with creases, are uniformly soldered andconnected on their overlapping surfaces, so that' the tube is in thismost simple manner made perfectly tight, According to this method, tubesof very -high resisting power can be produced at a comparatively lowexpense.

I claim- 1. A method consisting of coating a strip with solder, thenforming the strip while a cold condition into a spiral tubular form andnally immersing the tube into a molten mass to fuse the solder, forunitin the overlapped ortions of the strip and or sealing externa y thejoint formed at Vsuch overlapped portions.

2. A method consisting of coating a strip with soldering material,formnglsaid strip into a tube by spirally winding t e same on itselfwith its edge portions overlapping and when cold and finally immersingthe tube thus formed into a bath of soldering metal to unite saidoverlapped portions and to externally seal the joint between the same.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses. Y

NIOOLAUS HEID. Witnesses:

Josnr RUBAsoH, ALvEsTo S. HOGUE.

